title: Structure and relative stability of drum-like C4nN2n n = 3-8) cages and their hydrogenated products C4nH4nN2n (n = 3-8) cages.
abstract: The drum-like C4nNn (n = 3-8) cages and corresponding hydrogenated products C4n H4nN2n (n = 3-8) are studied at the DFT B3LYP/6-31G** level. Their structures, energies, and vibrational frequencies have been investigated. Comparison of heat of formation reveals that C32N16 with D8h symmetry in the C4nN2n (n = 3-8) series is a promising candidate as high energy density matter. The calculation of the DeltaG and DeltaH for the hydrogenation of C4nN2n (n = 3-8) shows that it is an exothermic reaction at 298 K and the C4nH4nN2n (n = 3-8) species are more stable than C4nN2n (n = 3-8) species. The analysis of molecular orbital and selected bond lengths of N-N and C-C provides another insight about their stability. Combined with the nucleus-independent chemical shifts (NICS) calculation, it is indicated that molecular stability for cage-shaped molecules depends on not only aromatic character but also the cage effect.
authors.affiliation: Department of Chemistry, East China University of Science and Technology, Shanghai, China.
authors.forename: Liang-Wei
authors.initials: LW
authors.lastname: Shi
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Jun-Hong
authors.initials: JH
authors.lastname: Zhou
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Kang
authors.forename: Min-Bo
authors.initials: MB
authors.lastname: Chen